Apparatus and method for acquisition of on-demand system information in wireless communications

ABSTRACT

A wireless terminal communicates over a radio interface with an access node of a radio access network (RAN), and method of operating same. The wireless terminal comprises receiver circuitry, processor circuitry, and transmitter circuitry. The processor circuitry is configured to initiate a first type system information block (SIB) acquisition process to receive a first type SIB. The first type SIB comprises scheduling information of a system information (SI) message, the SI message comprising at least one second type SIB, and an indication of broadcast status for the SI message, the indication indicating on-demand delivery. The receiver circuitry is configured to receive the first type SIB. The transmitter circuitry configured to transmit an SI request message to request the SI message. The processor circuitry is further configured to initiate an SI message acquisition process to receive the SI message and, in a case that a stored version of one of the at least one second type SIB is not valid, the first type SIB acquisition process is initiated upon a failure of the SI message acquisition process.

This application is a continuation of PCT application PCT/US2019/031669, filed 2019 May 10, and claims the priority and benefit of U.S. provisional application 62/669,838, filed May 10, 2018, both of which are entitled “APPARATUS AND METHOD FOR ACQUISITION OF ON-DEMAND SYSTEM INFORMATION IN WIRELESS COMMUNICATIONS” and both of which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The technology relates to wireless communications, and particularly to methods, apparatus, and techniques for requesting, transmitting, updating, and using system information (SI) in wireless communications.

BACKGROUND

In wireless communication systems, a radio access network generally comprises one or more access nodes (such as a base station) which communicate on radio channels over a radio or air interface with plural wireless terminals. In some technologies such a wireless terminal is also called a User Equipment (UE). A group known as the 3rd Generation Partnership Project (“3GPP”) has undertaken to define globally applicable technical specifications and technical reports for present and future generation wireless communication systems. The 3GPP Long Term Evolution (“LTE”) and 3GPP LTE Advanced (LTE-A) are projects to improve an earlier Universal Mobile Telecommunications System (“UMTS”) mobile phone or device standard in a manner to cope with future requirements.

In typical cellular mobile communication systems, the base station broadcasts on the radio channels certain information which is required for mobile stations to access to the network. In Long-Term Evolution (LTE) and LTE Advanced (LTE-A), such information is called “system information” (“SI”). Each access node, such as an evolved NodeB (“eNB”) or a gNB in the 5G New Radio (NR) System, broadcasts such system information to its coverage area via a Master Information Block (MIB) and several System Information Blocks (SIBs) on downlink radio resources allocated to the access node.

A wireless terminal (“UE”), after entering a coverage area of an eNB or gNB, is required to obtain all the MIB/SIBs which are necessary to access to the system. For sake of UEs under coverage, the eNB or gNB periodically broadcasts all MIB/SIBs relevant for offered services, where each type of MIB or SIBs is transmitted in a designated radio resource(s) with its own pre-determined/configurable frequency.

This all-broadcast-based periodic delivery method (e.g., collective broadcast of all SIBs, not just those necessary for system access) is efficient under a condition where many UEs are almost always flowing into the coverage area (such as a macro cell). However, this approach may result in wasting valuable radio resources in case of small cell deployment. Therefore, more efficient methods of SIB transmission are desired.

What is needed, therefore, and an example object of the technology disclosed herein, are methods, apparatus, and techniques for obtaining and/or updating SIBs in/of Other SI (Other SI SIBs), and also for making a determination of SI message acquisition process failure and remedial processes therefor.

SUMMARY

In one of its example aspects the technology disclosed herein concerns a wireless terminal which communicates over a radio interface with an access node of a radio access network (RAN), and method of operating same. In an example basic embodiment the wireless terminal comprises receiver circuitry, processor circuitry, and transmitter circuitry. The processor circuitry is configured to initiate a first type system information block (SIB) acquisition process to receive a first type SIB. The first type SIB comprises scheduling information of a system information (SI) message, the SI message comprising at least one second type SIB, and an indication of broadcast status for the SI message, the indication indicating on-demand delivery. The receiver circuitry is configured to receive the first type SIB. The transmitter circuitry configured to transmit an SI request message to request the SI message. The processor circuitry is further configured to initiate an SI message acquisition process to receive the SI message and, in a case that a stored version of one of the at least one second type SIB is not valid, the first type SIB acquisition process is initiated upon a failure of the SI message acquisition process.

In another of its example aspects the technology disclosed herein concerns base station apparatus which communicates over a radio interface with a user equipment. The base station apparatus comprises transmitter circuitry, receiver circuitry, and processor circuitry. The transmitter circuitry is configured to transmit a first type system information block (SIB). The first type SIB comprises scheduling information of a system information (SI) message, the SI message comprising at least one second type SIB, and an indication of broadcast status for the SI message, the indication indicating on-demand delivery. The receiver circuitry is configured to receive an SI request message to request the SI message. The processor circuitry is configured to use the transmitter circuitry to deliver the SI message. The first type SIB is re-acquired by the user equipment upon the user equipment failing on an SI message acquisition process to receive the SI message, in a case that a version of one of the at least one second type SIB stored in the user equipment is not valid.

In another of its example aspects the technology disclosed herein concerns a method in a wireless terminal which communicates over a radio interface with an access node of a radio access network (RAN). In an example basic mode the method comprises: initiating a first type system information block (SIB) acquisition process to receive a first type SIB; receiving the first type SIB; transmitting a system information (SI) request message to request an SI message; and initiating an SI message acquisition process to receive the SI message. The first type SIB comprises scheduling information of the SI message and an indication of broadcast status for the SI message, the indication indicating on-demand delivery. The SI message comprises at least one second type SIB. The first type SIB acquisition process is initiated upon a failure of the SI message acquisition process, in a case that a stored version of one of the at least one second type SIB is not valid.

In yet another of its example aspects the technology disclosed herein concerns a method in an access node of a radio access network (RAN) that communicates over a radio interface with a wireless terminal or user equipment. In an example basic mode the method comprises: transmitting a first type system information block (SIB); receiving a system information (SI) request message to request an SI message; and delivering the SI message. The first type SIB comprises scheduling information of the SI message and an indication of broadcast status for the SI message, the indication indicating on-demand delivery. The SI message comprises at least one second type SIB. The first type SIB is re-acquired by the user equipment upon the user equipment failing on an SI message acquisition process to receive the SI message, in a case that a version of one of the at least one second type SIB stored in the user equipment is not valid.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and advantages of the technology disclosed herein will be apparent from the following more particular description of preferred embodiments as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the various views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the technology disclosed herein.

FIG. 1 is a diagrammatic view showing transition states of a Radio Resource Control RRC state machine.

FIG. 2 is a schematic view showing an example generic communications system comprising a radio access node and a wireless terminal, wherein the wireless terminal requests, and the radio access node provides, Other system information (Other SI) when the wireless terminal is in a RRC_CONNECTED state.

FIG. 3 is a flowchart showing example, basic example acts or steps performed by a wireless terminal of the example generic communications system of FIG. 2.

FIG. 4-FIG. 7 are diagrammatic views illustrating differing example formats of a system information block (SIB) which comprises Minimal SI and which carries availability of Other system information (Other SI).

FIG. 8 is a diagrammatic view illustrating an exemplary message flow of on-demand based SI acquisition procedure.

FIG. 9A, FIG. 9B and FIG. 9C are diagrammatic views illustrating three options for an SI request procedure.

FIG. 10 is a diagrammatic view showing, e.g., a SystemInformationRequest message wherein a siRequest information element comprises a bit map.

FIG. 11 is a diagrammatic view illustrating an exemplary message flow of periodic broadcast based SI acquisition procedure.

FIG. 12 is a schematic view showing an example generic communications system comprising a wireless terminal configured to detect failure of a SI reception process involving an on-demand SI message, following a successful completion of an SI request.

FIG. 13A-FIG. 13D are diagrammatic view of differing implementations of SIB1 which comprise termination condition parameters.

FIG. 14 is a diagrammatic view illustrating an exemplary message flow including an on-demand based SI acquisition procedure which fails.

FIG. 15 is a flowchart showing basic, representative, example acts or steps performed by the wireless terminal of FIG. 12.

FIG. 16 is a flowchart showing basic, representative, example acts or steps performed by the access node of FIG. 12.

FIG. 17A is a diagrammatic view of a system information acquisition failure detector which comprises a SI window counter for making a determination of SI message acquisition process termination.

FIG. 17B is a diagrammatic view of a system information acquisition failure detector which comprises a SI message acquisition process timer for making a determination of SI message acquisition process termination.

FIG. 18A is a diagrammatic view showing a common termination condition for plural SI messages.

FIG. 18B is a diagrammatic view showing different termination conditions for different SI messages.

FIG. 19 is a schematic view showing an example generic communications system comprising a wireless terminal configured to detect failure of a SI reception process involving a periodically broadcasted SI message.

FIG. 20 is a diagrammatic view illustrating an exemplary message flow including a failed SI acquisition procedure for a periodically broadcasted SI message.

FIG. 21 is a flowchart showing basic, representative, example acts or steps performed by the wireless terminal of FIG. 19.

FIG. 22 is a flowchart showing basic, representative, example acts or steps performed by the access node of FIG. 19.

FIG. 23 is a diagrammatic view showing example electronic machinery which may comprise node electronic machinery or terminal electronic machinery.

DETAILED DESCRIPTION

In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the technology disclosed herein. However, it will be apparent to those skilled in the art that the technology disclosed herein may be practiced in other embodiments that depart from these specific details. That is, those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the technology disclosed herein and are included within its spirit and scope. In some instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the technology disclosed herein with unnecessary detail. All statements herein reciting principles, aspects, and embodiments of the technology disclosed herein, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

Thus, for example, it will be appreciated by those skilled in the art that block diagrams herein can represent conceptual views of illustrative circuitry or other functional units embodying the principles of the technology. Similarly, it will be appreciated that any flow charts, state transition diagrams, pseudocode, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

As used herein, the term “core network” can refer to a device, group of devices, or sub-system in a telecommunication network that provides services to users of the telecommunications network. Examples of services provided by a core network include aggregation, authentication, call switching, service invocation, gateways to other networks, etc.

As used herein, the term “wireless terminal” can refer to any electronic device used to communicate voice and/or data via a telecommunications system, such as (but not limited to) a cellular network. Other terminology used to refer to wireless terminals and non-limiting examples of such devices can include user equipment terminal, UE, mobile station, mobile device, access terminal, subscriber station, mobile terminal, remote station, user terminal, terminal, subscriber unit, cellular phones, smart phones, personal digital assistants (“PDAs”), laptop computers, netbooks, e-readers, wireless modems, etc.

As used herein, the term “access node”, “node”, or “base station” can refer to any device or group of devices that facilitates wireless communication or otherwise provides an interface between a wireless terminal and a telecommunications system. A non-limiting example of a base station can include, in the 3GPP specification, a Node B (“NB”), an enhanced Node B (“eNB”), a home eNB (“HeNB”), a 5G (New Radio [NR]) gNB, or some other similar terminology. Another non-limiting example of a base station is an access point. An access point may be an electronic device that provides access for wireless terminal to a data network, such as (but not limited to) a Local Area Network (“LAN”), Wide Area Network (“WAN”), the Internet, etc. Although some examples of the systems and methods disclosed herein may be described in relation to given standards (e.g., 3GPP Releases 8, 9, 10, 11, 12, or higher), the scope of the present disclosure should not be limited in this regard. At least some aspects of the systems and methods disclosed herein may be utilized in other types of wireless communication systems.

As used herein, the term “telecommunication system” or “communications system” can refer to any network of devices used to transmit information. A non-limiting example of a telecommunication system is a cellular network or other wireless communication system.

As used herein, the term “cellular network” can refer to a network distributed over cells, each cell served by at least one fixed-location transceiver, such as a base station. A “cell” may be any communication channel that is specified by standardization or regulatory bodies to be used for International Mobile Telecommunications-Advanced (“IMTAdvanced”). All or a subset of the cell may be adopted by 3GPP as licensed bands (e.g., frequency band) to be used for communication between a base station, such as a Node B, and a UE terminal. A cellular network using licensed frequency bands can include configured cells. Configured cells can include cells of which a UE terminal is aware and in which it is allowed by a base station to transmit or receive information.

As used herein, “system information” (“SI”) may include a Master Information Block (MIB) and several System Information Blocks (SIBs) which are provided on downlink radio resources allocated to an access node. The system information may be broadcast, and some types of system information may be provided on demand, e.g., upon receipt of a request for system information from a wireless terminal.

In various aspects of the technology disclosed herein, system information is classified into plural categories or types. In an example embodiment and mode, a first type of the system information is Minimum System Information (Minimum SI), minimally containing information required for UEs initially access to the network, periodically broadcasted by each access node (e.g. eNB for LTE, gNB for 5G Radio System). In some configurations, Minimum System SI may consist of MIB and a limited number of SIBs. The MIB may contain essential information for the radio system to help wireless terminals to synchronize to the serving access node and may also contain instruction how to obtain at least one of the essential SIBs. The Minimum SI may be also referred as “essential SI”, or first type system information.

A second type of system information, e.g., “Other system information, “Other SI”, or second type system information contains all the other types of information, i.e., all types of system information except the Minimum System Information. The Other SI may comprise several system information blocks (SIBs) that are not categorized as Minimum SI. The Other SI may be also referred as “non-essential SI”. However, the second type system information is not to be confused with SIB Type 2, which is a particular (second) system information block (SIB) that may be included in the Minimum System Information or may be a part of the Other SI.

In some example embodiment and modes described herein, for each of the SIBs the access node may choose to broadcast the SIB periodically, similar to the SIBs in Minimum SI. Alternatively, the access node may choose to refrain from transmitting the SIB until receiving a request of on-demand delivery from a UE. In this case, the access node may advertise the availability of on-demand delivery using Minimum SI.

As described herein, both an access node and a wireless terminal may manage respective Radio Resource Control (RRC) state machines. The RRC state machines transition between several RRC states including RRC_IDLE, RRC_INACTIVE and RRC_CONNECTED. FIG. 1 depicts the state transition diagram of the RRC states. From the vantage point of a wireless terminal e.g., user equipment (UE), the RRC states may be briefly characterized as follows:

RRC_IDLE:

-   -   A UE specific DRX (discontinuous reception) may be configured by         upper layers;     -   UE controlled mobility based on network configuration;     -   The UE:         -   Monitors a Paging channel;         -   Performs neighboring cell measurements and cell             (re-)selection;         -   Acquires system information.

RRC_INACTIVE:

-   -   A UE specific DRX may be configured by upper layers or by RRC         layer;     -   UE controlled mobility based on network configuration;     -   The UE stores the Access Stratum (AS) context;     -   The UE:         -   Monitors a Paging channel;         -   Performs neighboring cell measurements and cell             (re-)selection;         -   Performs RAN-based notification area updates when moving             outside the RAN-based notification area;         -   Acquires system information.

RRC_CONNECTED:

-   -   The UE stores the AS context.     -   Transfer of unicast data to/from UE.     -   At lower layers, the UE may be configured with a UE specific         DRX;     -   Network controlled mobility, i.e. handover within NR and to/from         E-UTRAN.;     -   The UE:         -   Monitors a Paging channel;         -   Monitors control channels associated with the shared data             channel to determine if data is scheduled for it;         -   Provides channel quality and feedback information;         -   Performs neighboring cell measurements and measurement             reporting;         -   Acquires system information.

The technology disclosed herein concerns, e.g., apparatus, methods, and procedures for obtaining and/or updating SIBs in/of Other SI (Other SI SIBs), and also includes making a determination of SI message acquisition process failure and remedial processes therefor.

FIG. 2 shows an example communications system 20 wherein radio access node 22 communicates over air or radio interface 24 (e.g., Uu interface) with wireless terminal 26. As mentioned above, the radio access node 22 may be any suitable node for communicating with the wireless terminal 26, such as a base station node, or eNodeB (“eNB”) or gNB, for example. The node 22 comprises node processor circuitry (“node processor 30”) and node transceiver circuitry 32. The node transceiver circuitry 32 typically comprises node transmitter circuitry 34 and node receiver circuitry 36, which are also called node transmitter and node receiver, respectively.

The wireless terminal 26 comprises terminal processor 40 and terminal transceiver circuitry 42. The terminal transceiver circuitry 42 typically comprises terminal transmitter circuitry 44 and terminal receiver circuitry 46, which are also called terminal transmitter 44 and terminal receiver 46, respectively. The wireless terminal 26 also typically comprises user interface 48. The terminal user interface 48 may serve for both user input and output operations, and may comprise (for example) a screen such as a touch screen that can both display information to the user and receive information entered by the user. The user interface 48 may also include other types of devices, such as a speaker, a microphone, or a haptic feedback device, for example.

For both the radio access node 22 and radio interface 24, the respective transceiver circuitries 22 include antenna(s). The transmitter circuit 34 and transmitter circuit 44 may comprise, e.g., amplifier(s), modulation circuitry and other conventional transmission equipment. The receiver circuit 36 and receiver circuit 46 may comprise, e.g., e.g., amplifiers, demodulation circuitry, and other conventional receiver equipment.

In general operation, access node, 22 and wireless terminal 26 communicate with each other across radio interface 24 using predefined configurations of information. By way of non-limiting example, the radio access node 22 and wireless terminal 26 may communicate over radio interface 24 using “frames” of information that may be configured to include various channels. In Long Term Evolution (LTE), for example, a frame, which may have both downlink portion(s) and uplink portion(s), may comprise plural subframes, with each LTE subframe in turn being divided into two slots. The frame may be conceptualized as a resource grid (a two dimensional grid) comprised of resource elements (RE). Each column of the two dimensional grid represents a symbol (e.g., an OFDM symbol on downlink (DL) from node to wireless terminal; an SC-FDMA symbol in an uplink (UL) frame from wireless terminal to node). Each row of the grid represents a subcarrier. The frame and subframe structure serves only as an example of a technique of formatting of information that is to be transmitted over a radio or air interface. It should be understood that “frame” and “subframe” may be utilized interchangeably or may include or be realized by other units of information formatting, and as such may bear other terminology (such as blocks, for example).

To cater to the transmission of information between radio access node 22 and wireless terminal 26 over radio interface 24, the node processor 30 and terminal processor 40 of FIG. 2 are shown as comprising respective information handlers. For an example implementation in which the information is communicated via frames, the information handler for radio access node 22 is shown as node frame/signal scheduler/handler 50, while the information handler for wireless terminal 26 is shown as terminal frame/signal handler 52.

The node processor 30 of radio access node 22 also includes system information (SI) generator 54. As described above, at least some of the system information generated and provided by the system information (SI) generator 54 is Minimum System Information (Minimum SI), also known as first type system information, represented by Minimum SI handler 54M. Some of the system information may be Other system information (Other SI), also known as second type system information, represented by Other SI handler 540 in FIG. 2. The wireless terminal 26 uses the system information (SI) generated by radio access node 22. Some of the Minimum SI may inform the wireless terminal 26 of the availability of the Other IS.

FIG. 2 illustrates a generic message 2-1 by which the node radio resource controller 54 may supply the Minimal SI to wireless terminal 26. In some example implementations, upon knowing of the availability of the Other SI, due to the message 2-1, for example, the wireless terminal 26 specifically requests the Other system information, in on-demand fashion, as described herein. The terminal processor 40 of wireless terminal 26 comprises, e.g., SI processor 56, to facilitate obtaining and use of system information.

The technology disclosed herein concerns, e.g., apparatus, methods, and procedures for obtaining and/or updating system information blocks (SIBs) in/of the Other SI (Other SI SIBs) in on-demand basis. Since in at least some of the example embodiments and modes the technology disclosed herein involves the Radio Resource Control (RRC) procedures, FIG. 2 shows terminal processor 40 as comprising node radio resource control (RRC) controller 60, e.g., node RRC controller 60. The node RRC controller 60 may execute an instance of the RRC state machine for each wireless terminal in which the access node 20 is in communication, with each instance keeping track of the RRC state transitions experienced by the wireless terminal associated with the respective instance.

FIG. 2 also shows the terminal processor 40 of wireless terminal 26 as comprising, in addition to terminal SI processor 56, a terminal RRC controller 70. The terminal RRC controller 70 includes or executes the RRC state machine discussed above, which transitions through the RRC states, as described above and shown in FIG. 2, for a communication involving wireless terminal 26.

FIG. 2 thus shows that the access node 22 comprises node processor 30, e.g., node processor circuitry 30, transmitter circuit 34, and, receiver circuit 36. The transmitter circuit 34 is configured to transmit the first type system information over a radio interface, the first type system information including availability of a SI message belonging to the second type system information. The receiver circuit 36 is configured to receive from the wireless terminal a request message to request delivery of the SI message which is available by on-demand basis. The transmitter circuit 34 is further configured to transmit the SI message to the wireless terminal.

FIG. 2 thus shows that the wireless terminal 26 communicates over radio interface 24 with access nodes, such as access node 22, of a radio access network (RAN). The wireless terminal 26 comprises receiver circuit 46, transmitter circuit 44, and terminal processor 40, e.g., terminal processor circuitry. The receiver circuit 46 is configured to receive first type system information over the radio interface. The terminal processor circuitry is configured to generate a request message to request the second type SIB which is available in an on-demand basis. The transmitter circuit 44 is configured to transmit the request message over the radio interface while in the connected state. The receiver circuit 46 is also configured to receive the SI message while in the connected state.

FIG. 3 shows example, representative acts or steps performed in conjunction with a generic method of operating a wireless terminal of a radio access network (RAN), such as wireless terminal 26 of FIG. 2. Act 3-1 comprises the wireless terminal acquiring, e.g., receiving, the Minimum SI that is broadcasted from the currently serving access node, e.g., access node 22. The Minimum SI may be broadcast in a message such as message 2-1 of FIG. 2. The Minimum SI may contain information about the Other SI, including the delivery method, e.g., periodic broadcast/on-demand, scheduling information, validity information, etc. Based on the information, the wireless terminal in act 3-2 may determine which SI message(s) to acquire by on-demand. As act 3-3, the wireless terminal may send a request message (depicted as message 2-2 of FIG. 2) to the access node, the request message indicating the SI message(s) that the wireless terminal desires to obtain. As act 3-4 the wireless terminal 26 may attempt to receive the requested SI message(s) which, e.g., was sent using message 2-3 of FIG. 2.

It was mentioned above that the first type system information includes availability of a SI message belonging to the second type system information, that the request message requests delivery of a SI message which is available by on-demand basis, and that the SI message is transmitted to the wireless terminal. It should be understood that reference herein to “a SI message belonging to the second type system information” means one or more pieces of Other system information (Other SI), e.g., one or more SI messages belonging to the second type system information. In some example situations indeed only one SI message may be advertised as available and accordingly periodically broadcasted or requested on-demand. But in other example situations plural SI messages (e.g., plural pieces of Other SI) are advertised as available, some of which may be periodically broadcasted and the others may be requested on-demand. Furthermore, it should be noted that in some configurations (e.g. the configuration presented in FIG. 7, or in FIG. 13A-D) the availability may be included in the scheduling information (e.g. schedulingInfoList described below).

In some configurations, the availability and delivery method information for Other SI SIBs may be included in SIB Type 1, one of the SIBs in the Minimum SI. FIG. 4 shows an example format of SIB Type 1, including schedulingInfoList, si-WindowLength, otherSIBInfoList, validity area identification (si-AreaID), and possibly other configuration parameters. The otherSIBInfoList is a list of otherSIBInfo, which comprises SIB-Type, an identifier of a SIB, validityInfo and validity information of the SIB (a value tag [valueTag], and other parameters, such as validity timer, etc.).

SIBs other than SIB1 are carried in SystemInformation (SI) messages and mapping of SIBs to SI messages is flexibly configurable by schedulingInfoList included in SIB1, with restrictions that: each SIB is contained only in a single SI message, only SIBs having the same scheduling requirement (periodicity given by si-periodicity) can be mapped to the same SI message. There may be multiple SI messages transmitted with the same periodicity.

In one configuration, each element, schedulingInfo, of schedulingInfoList may represent one SI message, comprising its periodicity (si-Periodicity), delivery method (deliveryMethod) indicating if this SIB is periodically broadcasted or to be transmitted upon request (on-demand), and associated SIB types (one or more SIB-Type's). The actual broadcast opportunity, e.g., timing/resources, of a given SI message may be determined by a pre-determined or a network-configured formula as a function of at least the corresponding periodicity. At each opportunity the broadcast of the SI message may occur within the duration of the window length (si-WindowLength). Hereafter a broadcast opportunity is also referred as a SI window. More than one SIB may be possibly transmitted on a same SI window.

In the configuration of FIG. 4 si-AreaID is common for all SI messages or SIB types, which means that all SIBs have the same validity area. Alternatively, in another configuration, each SI message may have a designated validity area. FIG. 5 shows an example format of SIB1 for such a configuration wherein each SI message may have a designated validity area. Furthermore, in another configuration, having an example format such as shown in FIG. 6, each SIB type may have a designated validity area. Thus, in differing implementations, the system information (SI) generator 54 of FIG. 2, working with node frame/signal scheduler/handler 50, generates the differing formatted SI messages of FIG. 4, FIG. 5, and FIG. 6, for transmission by node transmitter circuitry 34 over radio interface 24.

FIG. 7 is an alternative format for SIB1, which is logically equivalent to the format shown in FIG. 4. The si-BroadcastStatus information element of FIG. 7 may be functionally identical to deliveryMode information element described earlier. In one configuration, the information element sibValueTagList may comprise a list of value tags for the available SIBs included in schedulingInfoList, in the order of the SIB numbering scheme (e.g. SIB2, SIB3, SIB4, SIB5, . . . ). In another configuration, sibValueTagList may comprise a list of value tags for the available SIBs (included in schedulingInfoList) as well as the non-available SIBs (not included in schedulingInfoList), in the order of the SIB numbering scheme (e.g. SIB2, SIB3, SIB4, SIB5, . . . ). In this case, a pre-determined value may be set to the value tag for a non-available SIB. Accordingly, the si-BroadcastStatus information element may be used for indicating broadcast status (e.g. the broadcast status being either periodic broadcast or on-demand basis).

FIG. 8 is an exemplary message flow diagram of on-demand based SI acquisition procedure. As shown by act 8-0, wireless terminal 26 in either RRC_IDLE, RRC_INACTIVE or RRC_CONNECTED state stores the content of SIB#A with the validity information, valueTag=a, si-AreaID=2, which the wireless terminal has previously received. From the currently serving access node, as act 8-1 the wireless terminal may obtain SIB1 as Minimum SI. As shown in FIG. 4, FIG. 5, FIG. 6, and FIG. 7, the SIB1 includes the scheduleInfoList, which in turn may include one or more schedulingInfo information elements. An example scheduleInfoList for this scenario is shown in Table 1, wherein the k′th schedulingInfo indicates that the SI message associated with this schedulingInfo (SI#k, hereafter), containing SIB#A, will be available by on-demand delivery. Furthermore, the otherSIBInfo corresponding to SIB#A indicates that the validity information of SIB#A is valueTag=b, si-AreaID=3. It is assumed hereafter that whenever the wireless terminal receives SIB1, it has already received MIB beforehand.

TABLE 1 ... schedulingInfoList {   ...   k'th schdulingInfo (SI#k) {     ...     deliveryMethod = on-demand     SIB-type = A     ...   }   ...   } } ... otherSIBInfoList {   ...   otherISBInfo {     SIB-type = A     ValidityInfo {       valueTag = b       ...     }     ...   }   ... } ... si-AreaID = 3 ...

Knowing that the stored SIB#A is now invalid, the wireless terminal may decide to obtain a valid version of SIB#A, and may initiate the SI request procedure represented by act 8-2 and explained herein. After the SI request procedure has a successful result, the wireless terminal may start the SI reception procedure, shown generally as act 8-3 in FIG. 8. In the SI reception procedure the wireless terminal monitors signals from the access node in the designated SI windows derived from the scheduling information (scheduleInfo) in the SIB1, and thereby attempts to receive the requested SI#k. The SI windows are shown by dotted rectangles in FIG. 8. FIG. 8 shows by act 8-3 a a first transmission of the requested SI#k, which is unsuccessful, and by act 8-3 b a second transmission of the requested SI#k, which is successful. A tail of a vertical down-pointing arrow in the SI reception procedure depiction of FIG. 8 is associated with start of the SI reception procedure, while the head of the same vertical down-pointing arrow is associated with end of the SI reception procedure (at successful reception of the SI#k). FIG. 8 also shows by act 8-4 that other transmissions of the requested system information may also be made even after the wireless terminal has successfully received the sought SI#k.

In one configuration, the wireless terminal may use a counter, which is incremented at every SI window of a particular SI message, e.g. SI#k. In this configuration, the SI reception procedure may end when the requested SI message(s) are successfully received, or when the counter reaches a maximum counter value. In another configuration the wireless terminal starts a timer at the beginning of the SI reception procedure. In this configuration, the SI reception procedure may end when the requested SI message(s) are successfully received, or when the timer expires. The maximum counter value, or the timer value, which may be common for all SI messages or per-SI message basis, may be pre-configured or configured by network via system information. The conditions for the wireless terminal to end the SI reception process is referred as “termination conditions” herein.

FIG. 9A, FIG. 9B and FIG. 9C show three options for the SI request procedure. In FIG. 9A, which may be applicable to wireless terminals in any of the RRC states, the request of on-demand delivery for SI messages may be accomplished by sending a Random Access Preamble, which may comprise a sequence selected from a set of available sequences configured by the access node via Minimum SI. A given sequence is identified by a Preamble Index. When the access node detects the transmission of a preamble sequence, it may respond to it with Random Access Response, which includes the Preamble Index corresponding to the sequence. Upon receiving, the wireless terminal may validate that the Preamble index in the Random Access Response matches the one associated with the preamble sequence, and then send to the access node SystemInformationRequest message that includes the identity of the SI messages (e.g. SI#k) that the wireless terminal desires to receive. In response, the access node may send a SystemInformation message acknowledging the request, indicating that the requested SI message(s) will be broadcasted from the next SI window scheduled for the requested SI message(s).

In one configuration, the access node may include in Minimum SI a set of Preamble indices, each of which is designated for requesting on-demand delivery of one or more specific SI messages. FIG. 9B illustrates an example SI request procedure using this configuration, where the wireless terminal in any RRC state may transmit Random Access Preamble sequence given by the Preamble Index associated with the SI message(s) that the wireless terminal has selected. When the wireless terminal receives Random Access Response including the Preamble Index, it may consider that the request procedure is successful.

The SI request procedure in FIG. 9C may be applicable to wireless terminals in RRC_CONNECTED, wherein the SystemInformationRequest message is sent without the random access preamble/response.

In any of the three options disclosed above, the wireless terminal may proceed to the SI reception procedure if the SI request procedure is successful. Otherwise, the wireless terminal may think that the serving cell (controlled by the access node) is barred, which will invoke a cell reselection.

The SystemInformationRequest message shown in FIG. 9A or FIG. 9C may include an information element (e.g. siRequest) to indicate which SI message(s) that the wireless terminal desires to receive. In one configuration, as shown in FIG. 10, the siRequest may comprise a bit map, wherein each bit corresponds to a schedulingInfo information element in SIB1 of the current serving cell, the bits arranged in the order of schedulingInfo information elements. By doing so, each bit of the bit map may correspond to a specific SI message. Alternatively, siRequest may carry a field indicating that the wireless terminal desires to receive at least one on-demand basis SI message. In this case, the access node may start broadcasting all of the on-demand basis SI messages for a pre-configured duration. The SystemInformation message shown in FIG. 9A or FIG. 9C may include siAck, an information element for acknowledging siRequest. In one configuration, siAck may comprises the same bit map as the one in SystemInformationRequest, indicating the SI message(s) to be broadcasted. Alternatively, siAck may comprise one Boolean field, indicating whether the request has been accepted or not.

FIG. 11 is an exemplary message flow diagram of SI acquisition procedure for a SI message broadcasted periodically. Act 11-0 comprises the wireless terminal 26, in either RRC_IDLE, RRC_INACTIVE or RRC_CONNECTED state, storing the content of SIB#A with the validity information, e.g., valueTag=a and si-AreaID=2. Act 11-1 comprises the wireless terminal 26 obtaining, from the currently serving access node 22, SIB1 as Minimum SI, which, as understood from previous description, includes one or more schedulingInfo information elements. In the scenario of FIG. 11, and as shown by Table 2, the k′th schedulingInfo information element indicates that the SI message associated with this schedulingInfo (SI#k, hereafter), containing SIB#A, is currently broadcasted periodically. Furthermore, the SIB1 specifies (see Table 2) that otherSIBInfo corresponding to SIB#A indicates that the validity information of SIB#A is now valueTag=b and si-AreaID=3.

Knowing that the stored SIB#A is now invalid, as act 11-3 the wireless terminal 26 begins an SI reception procedure wherein the wireless terminal may attempt to acquire the SI message (SI#k) in the SI windows specified in SIB1. In FIG. 11, act 11-3 a illustrates an unsuccessful SI message reception attempt in a first SI window for SI#k, followed by act 11-3 b which is a successful SI message reception in a second SI window for SI#k, Thus, as shown in FIG. 11, if the SI message is not received by the end of the SI window (as was the case for act 11-3 a), the wireless terminal 26 may repeat reception at the next SI window occasion for the concerned SI message until it successfully receives the SI message (as was done in act 11-3 b).

TABLE 2 ... schedulingInfoList {   ...   k'th schdulingInfo (SI#k) {     ...     deliveryMethod = broadcast     SIB-type = A     ...   }   ...   } } ... otherSIBInfoList {   ...   otherISBInfo {     SIB-type = A     ValidityInfo {       valueTag = b       ...     }     ...   }   ... } ... si-AreaID = 3 ...

Unsuccessful Attempted Reception of on-Demand System Information

FIG. 12 shows an example communications system 20(12) comprising wireless terminal 26(12) configured to detect failure of a SI reception process involving an on-demand SI message, following a successful completion of an SI request. The access node 22(12) and wireless terminal 26(12) of FIG. 12 are essentially identical to the respective access node 22 and wireless terminal 26 of FIG. 2, except as otherwise indicated herein. In terms of likeness, for example, the radio access node 22(12) comprises node processor 30 and node transceiver circuitry 32, with the node processor 30 comprising, e.g., node frame/signal scheduler/handler 50, system information (SI) generator 54, and node RRC controller 60. Similarly, the wireless terminal 26(12) comprises terminal processor 40, terminal transceiver circuitry 42, with terminal processor 40 comprising terminal frame/signal scheduler/handler 52, system information (SI) processor 56, and terminal RRC controller 70.

FIG. 12 also shows that wireless terminal 26(12) comprises system information acquisition failure detector 80. The terminal processor 40, and particularly SI processor 56, may comprise or constitute the system information acquisition failure detector 80. The system information acquisition failure detector 80 is configured to make a determination of a failure of the SI message acquisition process. The system information acquisition failure detector 80 may make such failure determination based on a termination condition, as herein explained.

The system information generator 54 of radio access node 22(12) is configured to generate first type system information. For the example embodiment and mode of FIG. 12, and in an example, non-limiting manner shown in FIG. 13, the first type system information comprises (information elements or the like which indicate): availability of second type SI messages; scheduling information of each of the SI messages; a delivery mode for each of the second type SI messages; and, a configuration parameter to configure at least one termination condition for determination of a failure of an SI message acquisition process for the on-demand based second type SI messages.

As understood herein, a second type SI message comprises at least one system information block (SIB), and the delivery mode may be either periodic broadcast or on-demand basis. The transmitter circuitry 36 of radio access node 22(12) is configured to transmit the first type system information over the radio interface 24 to the wireless terminal 26(12), as shown by arrow 12-1 in FIG. 12

As in the example embodiment and mode of FIG. 2, the on-demand Other SI request generator 72 of wireless terminal 26(12) may request at least one second type SI using a request message as indicated by arrow 12-2 in FIG. 12. The second type SI request message depicted by arrow 12-2 is received by node receiver circuitry 36. The node processor 30, and particularly the SI generator 54, generates the requested (second type) SI message in one or more windows of transmission, the transmission of the requested SI message being depicted by arrow 12-3 in FIG. 12.

As mentioned above, system information acquisition failure detector 80 may make a determination of a failure of the SI message acquisition process. When so doing, in an example embodiment and mode, the terminal processor 40, working in response to or with system information acquisition failure detector 80, is configured to initiate acquisition of the first type system information. That is, the terminal processor 40 is configured, upon a failure of the SI message acquisition process, to initiate acquisition of the first type system information, e.g., to again request the first type system information (Minimum SI) from the radio access node 22(12). In FIG. 12 such request for first type system information is depicted by arrow 12-4.

FIG. 13A is an exemplary format of SIB1, which is based on the format shown in FIG. 7 with an additional information element si-MaxAcqAttempts. The information element si-MaxAcqAttempts provides a termination condition for the SI reception procedure, indicating the maximum number of SI message reception opportunities (e.g. SI windows) allowed before the end of the SI reception procedure. FIG. 13B is an alternative format of SIB1, wherein the information element ue-TimersAndConstants includes a timer configuration (T#x) to be used as a termination condition for the SI reception procedure.

FIG. 14 is an exemplary message flow diagram of on-demand based SI acquisition procedure wherein system information acquisition failure is detected. As shown by act 14-0, wireless terminal 26, in either RRC_IDLE, RRC_INACTIVE or RRC_CONNECTED state stores the content of SIB#A with the validity information, valueTag=a, si-AreaID=2, which the wireless terminal has previously received. From the currently serving access node, as act 14-1 the wireless terminal may obtain SIB1 as Minimum SI, e.g., first type system information. Obtaining of the SIBI is depicted by arrow 12-1 in FIG. 12. As shown in FIG. 13, the SIB1 includes the scheduleInfoList, which in turn may include one or more schedulingInfo information elements. An example scheduleInfoList for this scenario is shown in previously-discussed Table 1, wherein the k′th schedulingInfo indicates that the SI message associated with this schedulingInfo (SI#k, hereafter), containing SIB#A, will be available by on-demand delivery. Furthermore, the otherSIBInfo corresponding to SIB#A indicates that the validity information of SIB#A is valueTag=b, si-AreaID=3. It is assumed hereafter that whenever the wireless terminal receives SIB1, it has already received MIB beforehand.

Knowing that the stored SIB#A is now invalid, the wireless terminal may decide to obtain a valid version of SIB#A, and may initiate the SI request procedure represented by act 14-2 and explained herein and illustrated by arrow 12-2 in FIG. 12. After the SI request procedure has a successful result, the wireless terminal may start the SI reception procedure, shown generally as act 14-3 in FIG. 14. In the SI reception procedure the wireless terminal monitors signals from the access node (depicted by arrow 12-3 in FIG. 12) in the designated SI windows derived from the scheduling information (scheduleInfo) in the SIB1, and thereby attempts to receive the requested SI#k. The SI windows are shown by dotted rectangles in FIG. 14. FIG. 14 shows by act 14-3 a, act 14-3 b, and act 14-3 c three successive transmissions of the requested SI#k, all of which are unsuccessful. A tail of a vertical down-pointing arrow in the SI reception procedure depiction of FIG. 14 is associated with start of the SI reception procedure, while the head of the same vertical down-pointing arrow is associated with end of the SI reception procedure. In FIG. 14, the SI reception procedure fails. Failure of the SI reception procedure is determined by system information acquisition failure detector 80 which, as indicated above, makes a determination of a failure of the SI message acquisition process based on a termination condition. Examples of the termination condition are described below.

Upon detection of failure of the SI message acquisition process, as act 14-4 the terminal processor 40 initiates (re)acquisition of the first type system information, e.g., the MINIMAL SI or SIB1, as shown by arrow 12-4 in FIG. 12. The wireless terminal 26(12) thus attempts to again acquire the first type system information, in hopes that the SI message acquisition process can thereafter be repeated and perhaps in such repeat of the SI message acquisition process the requested SI message will be obtained. In an example implementation, the wireless terminal 26(12) may optionally reacquire MIB prior to reacquisition of SIB1. Accordingly, not having a valid version of a stored SIB, upon detection of failure of the SI message acquisition process, the terminal processor 40 initiates (re)acquisition of the first type system information.

FIG. 15 shows basic, representative, example acts or steps performed by the wireless terminal 26(12) of FIG. 12. Act 15-1 comprises receiving the first type system information (SI) from the base station apparatus. As mentioned above, the first type system information comprises: availability of a second type SI message, the second type SI message comprising at least one system information block (SIB); scheduling information for the SI message; an indication of a delivery mode for the second type SI message, the delivery mode being either periodic broadcast or on-demand basis; and, at least one termination condition for determination of a failure of an SI message acquisition process for the on-demand based second type SI message. Act 15-2 comprises transmitting an SI request message to request at least one second type SI message indicated as on-demand delivery. Act 15-3 comprises initiating the SI message acquisition process. Act 15-4 comprises determining a failure of the SI message acquisition process. Act 15-5 comprises, upon a failure of the SI message acquisition process, initiating acquisition of the first type system information.

FIG. 16 is a flowchart showing basic, representative, example acts or steps performed by the access node 22(12) of FIG. 12. Act 16-1 comprises transmitting first type system information (SI). The first type SI has been described above. Act 16-2 comprises receiving an SI request message to request at least one second type SI message. Act 16-3 comprises delivering the requested SI message. As understood from above, the requested SI message may be sent periodically, repeatedly transmitted at a predetermined interval, for a predetermined length of time.

It was mentioned above that, in one configuration, the wireless terminal may use a counter, which is incremented at every SI window of a particular SI message, e.g. SI#k, and that the SI reception procedure may end when the requested SI message(s) are successfully received, or when the counter reaches a maximum counter value. In some configurations, the maximum counter value may be configured by SIB1 (e.g. si-MaxAcqAttempts shown in FIG. 13A). FIG. 17A shows the system information acquisition failure detector 80 as comprising such counter as SI window counter 82. Thus in one example implementation of the FIG. 12 example embodiment and mode, the termination condition may comprise SI window counter 82 counting up to reach a maximum value, or counting down from a pre-set value to zero. Such maximum or pre-set value may be configured by the radio access node 22(12). The SI window counter 82 is incremented (or decremented) in a case in which the requested SI message was not received by the end of one reception opportunity, e.g., a case in which the requested SI message was not received by the end of an SI window.

It was further mentioned above that, in another configuration the wireless terminal may start a timer at the beginning of the SI reception procedure, and that the SI reception procedure may end when the requested SI message(s) are successfully received, or when the timer expires. In some configuration, the timer is configured by SIB1 (e.g. the timer configuration T#x in FIG. 13B). FIG. 17B shows the system information acquisition failure detector 80 as comprising such a timer: SI message acquisition process timer 84. Thus in another example implementation of the FIG. 12 example embodiment and mode, the termination condition may comprise SI message acquisition process timer 84 expiration of a timer configured by the base station apparatus. The SI message acquisition process timer 84 is started at the beginning of the SI message acquisition process. The timer expiration value may be configured by the radio access node 22(12).

As understood from above, the Other SI may comprise one or more (Other) SI messages, also known as second type SI messages. In one example implementation, as reflected by FIG. 18A, the termination condition may be common for plural, e.g., all, SI messages. That is, in the FIG. 18A implementation, the maximum counter value in the case of FIG. 17A, or the timer value in the case of FIG. 17B, may be common for all SI messages. In this case, the counter value configuration or the timer configuration in Minimum SI (e.g. si-MaxAcqAttempts in FIG. 13A, or T#x in FIG. 13B) may comprise a single parameter. Alternatively, as shown in the example implementation of FIG. 18B, the termination condition may be configured on a per-SI message basis, e.g., uniquely configured for one or more (Other SI) SI messages. In this case, the counter value configuration or the timer configuration in Minimum SI (e.g. si-MaxAcqAttempts in FIG. 13A, or T#x in FIG. 13B) may comprise a list of parameters, each of which configures a corresponding SI message. In either the FIG. 18A or FIG. 18B implementations, the termination condition(s), whether common or not common, e.g., unique, may be pre-configured or configured by network via system information. Thus, the condition for the wireless terminal to end the SI reception process is referred as a “termination condition” herein.

The foregoing is now discussed in context of a more general 3GPP TS SI acquisition procedure for a UE to acquire the AS- and NAS information. This more 3GPP TS procedure applies to UEs in RRC_IDLE, in RRC_INACTIVE and in RRC_CONNECTED. The UE in RRC_IDLE and RRC_INACTIVE shall ensure having a valid version of (at least) the MIB, SIB1 as well as SIB X through SIB Y (depending on support of the concerned RATs for UE controlled mobility). The UE in RRC_CONNECTED shall ensure having a valid version of (at least) the MIB, SIB1 as well as SIB X (depending on support of mobility towards the concerned RATs).

For the acquisition of MIB and SIB1, the UE shall perform the acts below (wherein reference to any “section”, “clause”, or “sub-clause” is to the respective section, clause, or sub-clause of 3GPP TS 38.331.)

1> if the cell is a PSCell: 2> acquire the MIB; 2> perform the actions specified in section 5.2.2.4.1; 1> else: 2> acquire the MIB; 2> if the UE is unable to acquire the MIB; 3> perform the actions as specified in clause 5.2.2.5; 2> else: 3>  perform the actions specified in section 5.2.2.4.1. 2> acquire the SIB1, 2> if the UE is unable to acquire the SIB1: 3> perform the actions as specified in clause 5.2.2.5; 2> else: 3>perform the actions specified in section 5.2.2.4.2.

From the foregoing it is understood that the UE shall apply the SI acquisition procedure as defined above upon cell selection (e.g. upon power on), cell-reselection, return from out of coverage, after reconfiguration with sync completion, after entering NR-RAN from another RAT, upon receiving an indication that the system information has changed, upon receiving a PWS notification, upon failing to acquire an SI message; whenever the UE does not have a valid version in the stored SI.

From the foregoing it is understood that, in an example implementation, when acquiring an SI message, the UE may perform the following acts:

-   -   1> determine the start of the SI-window for the concerned SI         message.     -   1> if SI message acquisition is not triggered due to UE request:         -   2> receive DL-SCH using the SI-RNTI from the start of the             SI-window and continue until the end of the SI-window whose             absolute length in time is given by si-WindowLength, or             until the SI message was received;         -   2> if the SI message was not received by the end of the             SI-window, repeat reception at the next SI-window occasion             for the concerned SI message;     -   1> else if SI message acquisition is triggered due to UE         request:         -   2> Set the SI window counter 82 to 0 (or Start SI message             acquisition process timer 84);         -   2>[FFS receive DL-SCH using the SI-RNTI from the start of             the SI-window and continue until the end of the SI-window             whose absolute length in time is given by si-WindowLength,             or until the SI message was received];         -   2>[FFS if the SI message was not received by the end of the             SI-window, increment the SI window counter 82, repeat             reception at the next SI-window occasion for the concerned             SI message];         -   2> if the SI window counter 82 is equal to configured             maximum value or counted down to zero (or timer SI message             acquisition process timer 84 expires)             -   3> Initiate the SI acquisition procedure.

When the UE acquires a MIB or a SIB1 or a SI message in a currently camped/serving cell as described in clause 5.2.2.3, the UE shall store the acquired SI. A version of the SI that the UE stored is out of date after 3 hours. The UE may use such a stored version of the SI e.g. after cell re-selection, upon return from out of coverage or after the reception of SI change indication. The storage and management of the stored SI in addition to the SI relevant for the current camped/serving cell is left to UE implementation. The UE shall:

-   -   1> delete any stored version of a SIB after 3 hours from the         moment it was successfully confirmed as valid;     -   1> if UE has stored version of any SIB:         -   2> for each SIB:             -   3> if the stored SIB is area specific SIB and if                 systemInfoAreaIdentifier and systemInfoValueTag included                 in the SIB1 received from the currently camped/serving                 cell are identical to the systemInfoAreaIdentifier and                 systemInfoValueTag associated with stored version of                 that SIB; or             -   3> if the stored SIB is cell specific and if                 systemInfoValueTag included in the SIB1 received from                 the currently camped/serving cell is identical to the                 systemInfoValueTag associated with stored version of                 that SIB;                 -   4> consider the stored SIB as valid for the cell;             -   3> else:                 -   4> (re)acquire the corresponding SI message as                     specified in clause 5.2.2.3.     -   1> if UE has no stored version of a SIB:         -   2> (re)acquire the corresponding SI message as specified in             clause 5.2.2.3.

Unsuccessful Attempted Reception of Broadcasted System Information

The previous embodiments disclose, e.g., procedure(s) for acquiring an SI message currently broadcasted periodically, wherein the wireless terminal may continue the SI reception procedure until successful completion. This operation may be valid if the concerned SI message is assumed to be broadcasted forever. By the introduction of on-demand SI, however, the assumption is not guaranteed to be true. For instance, when the wireless terminal sees deliveryMode=broadcast in SIB1 for the SI message of concern, it is possible that the access node may be temporarily broadcasting the SI message in response to a request from another wireless terminal, and that the access node may stop the periodic broadcast eventually.

Whereas the example communications system 20(12) of FIG. 12 primarily concerns unsuccessful attempted reception of on-demand system information, FIG. 19 shows an example communications system 20(17) comprising wireless terminal 26(17) configured to detect failure of a SI reception process involving a periodically broadcast SI message. The access node 22(17) and wireless terminal 26(17) of FIG. 19 are essentially identical to the respective access node 22 and wireless terminal 26 of FIG. 2 and FIG. 12, except as otherwise indicated herein. In terms of likeness, for example, the radio access node 22(17) comprises node processor 30 and node transceiver circuitry 32, with the node processor 30 comprising, e.g., node frame/signal scheduler/handler 50, system information (SI) generator 54, and node RRC controller 60. Similarly, the wireless terminal 26(17) comprises terminal processor 40, terminal transceiver circuitry 42, with terminal processor 40 comprising terminal frame/signal scheduler/handler 52, system information (SI) processor 56, and terminal RRC controller 70.

FIG. 19 shows that wireless terminal 26(17) also comprises system information acquisition failure detector 80. As in the case of FIG. 12, terminal processor 40, and particularly SI processor 56, may comprise or constitute the system information acquisition failure detector 80. The system information acquisition failure detector 80 is configured to make a determination of a failure of the SI message acquisition process. The system information acquisition failure detector 80 may make such failure determination based on a termination condition, as herein explained.

As in the FIG. 12 example embodiment and mode, system information generator 54 of radio access node 22(12) is configured to generate first type system information. For the example embodiment and mode of FIG. 19, and in the example, non-limiting manner shown in FIG. 13, the first type system information comprises (information elements or the like which indicate): availability of second type SI messages; scheduling information of each of the SI messages; a delivery mode for each of the second type SI messages; and, a configuration parameter to configure at least one termination condition for determination of a failure of an SI message acquisition process for the on-demand based second type SI messages. As understood herein, a second type SI message comprises at least one system information block (SIB), and the delivery mode may be either periodic broadcast or on-demand basis. The transmitter circuitry 36 of radio access node 22(17) is configured to transmit the first type system information over the radio interface 24 to the wireless terminal 26(17), as shown by arrow 19-1 in FIG. 19.

In the FIG. 19 example embodiment and mode it is assumed that wireless terminal 26(17) is presently concerned with acquiring a second type SI message for which the delivery mode is periodic broadcast. As such, the terminal processor 40 is controlling terminal receiver 46 to initiate a SI message acquisition process for a periodically broadcasted second type SI message. But it may turn out, however, after initiating the SI message acquisition process, that the expected periodically broadcasted second type SI message(s) are not received. Non-receipt of the periodically broadcasted second type SI message(s) may be for any of several reasons, including the fact that the broadcast of the periodically broadcasted second type SI message was at the behest of another wireless terminal, with the wireless terminal 26(17) essentially being a third-party beneficiary of the broadcasts, and the access node has by now terminated the broadcast of the second type SI message intended for the another wireless terminal.

Thus, as in the FIG. 12 example embodiment and mode, system information acquisition failure detector 80 may make a determination of a failure of the SI message acquisition process. When so doing, in an example embodiment and mode, the terminal processor 40, working in response to or with system information acquisition failure detector 80, is configured to initiate acquisition of the first type system information. That is, the terminal processor 40 is configured, upon a failure of the SI message acquisition process involving a periodically broadcasted second type SI message, to initiate acquisition of the first type system information, e.g., to again request the first type system information (Minimum SI) from the radio access node 22(17). In FIG. 19 such request for first type system information is depicted by arrow 19-4 (there being no arrow 19-2 or arrow 19-3 in FIG. 19).

FIG. 20 is an exemplary message flow diagram of a periodic broadcast based SI acquisition procedure wherein system information acquisition failure is detected. As shown by act 20-0, wireless terminal 26, in either RRC_IDLE, RRC_INACTIVE or RRC_CONNECTED state stores the content of SIB#A with the validity information, valueTag=a, si-AreaID=2, which the wireless terminal has previously received. From the currently serving access node, as act 20-1 the wireless terminal may obtain SIB1 as Minimum SI, e.g., first type system information. Obtaining of the SIB1 is also depicted by arrow 19-1 in FIG. 19. As shown in FIG. 13, the SIB1 includes the scheduleInfoList, which in turn may include one or more schedulingInfo information elements. An example scheduleInfoList for this scenario is shown in previously-discussed Table 3, wherein the k′th schedulingInfo indicates that the SI message associated with this schedulingInfo (SI#k, hereafter), containing SIB#A, will be available by broadcast. Furthermore, the otherSIBInfo corresponding to SIB#A indicates that the validity information of SIB#A is valueTag=b, si-AreaID=3. It is assumed hereafter that whenever the wireless terminal receives SIB1, it has already received MIB beforehand.

Having received the SIB1 as Minimum SI, e.g., first type system information, the wireless terminal 26(17) knows when the radio access node 22(17) is expected to broadcast the system information for the sought second type SI, e.g., SIB#A. As such, the terminal processor 40 of wireless terminal 26(17) begins the SI reception procedure (represented by act 20-3 in FIG. 20).

In the SI reception procedure 20-3, the wireless terminal monitors signals from the access node attempts to obtain the SI messages in the designated SI windows derived from the scheduling information (scheduleInfo) in the SIB1, and thereby attempts to receive the requested SI#k. The SI windows are shown by dotted rectangles in FIG. 20. FIG. 20 shows by act 20-3 a, act 20-3 b, and act 20-3 c three successive transmissions of the requested SI#k, all of which are unsuccessful. A tail of a vertical down-pointing arrow in the SI reception procedure depiction of FIG. 20 is associated with start of the SI reception procedure, while the head of the same vertical down-pointing arrow is associated with end of the SI reception procedure. In FIG. 20, the SI reception procedure 20-3 utterly fails. Failure of the SI reception procedure is determined by system information acquisition failure detector 80 which, as indicated above, makes a determination of a failure of the SI message acquisition process based on a termination condition. Examples of the termination condition are described herein.

Upon detection of failure of the SI message acquisition process, as act 20-4 the terminal processor 40 initiates (re)acquisition of the first type system information, e.g., the MINIMAL SI or SIB1, as shown by arrow 20-4 in FIG. 20. The wireless terminal 26(14) thus attempts to again acquire the first type system information, in hopes that the SI message acquisition process can thereafter be repeated and perhaps in such repeat of the SI message acquisition process the requested SI message will be obtained. In an example implementation, the wireless terminal 26(14) may optionally reacquire MIB prior to reacquisition of SIB1. Accordingly, not having a valid version of a stored SIB, upon detection of failure of the SI message acquisition process, the terminal processor 40 initiates (re)acquisition of the first type system information.

FIG. 21 is a flowchart showing basic, representative, example acts or steps performed by the wireless terminal of FIG. 19. Act 21-1 comprises receiving first type system information (SI) from the base station apparatus. As indicated previously, the first type system information comprises: availability of a second type SI message; scheduling information for the SI message; an indication of a delivery mode for the second type SI message, the delivery mode being either periodic broadcast or on-demand basis; and, at least one termination condition for determination of a failure of an SI message acquisition process. Act 21-2 comprises initiating the SI message acquisition process for a periodically broadcasted second type SI message. Act 21-3 comprises determining a failure of the SI message acquisition process. Act 21-4 comprises, upon a failure of the SI message acquisition process, initiating acquisition of the first type system information.

FIG. 22 is a flowchart showing basic, representative, example acts or steps performed by the access node of FIG. 19. Act 22-1 comprises transmitting first type system information (SI) from the base station apparatus. The first type system information comprises, e.g., configuration parameters to configure for at least one termination condition for determination of a failure of an SI message acquisition process. Act 22-2 comprises broadcasting the periodic broadcast-based SI messages.

As in the FIG. 12 embodiment and mode, wireless terminal 26(17) may use a counter, which is incremented at every SI window of a particular SI message, e.g. SI#k, and may end the SI reception procedure when the requested SI message(s) are successfully received, or when the counter reaches a maximum counter value. The system information acquisition failure detector 80 of FIG. 19 may comprise the aforementioned SI window counter 82, shown in FIG. 17A, which may count up to reach a maximum value, or count down from a pre-set value to zero. Such maximum or pre-set value may be configured by the radio access node 22(17). The SI window counter 82 is incremented (or decremented) in a case in which the requested SI message was not received by the end of one reception opportunity, e.g., a case in which the requested SI message was not received by the end of an SI window.

Also as in the FIG. 12 embodiment and mode, wireless terminal 26(17) may start a timer at the beginning of the SI reception procedure, and may end the SI reception procedure when the requested SI message(s) are successfully received, or when the timer expires. The system information acquisition failure detector 80 of FIG. 19 may comprise the aforementioned SI message acquisition process timer 84 shown in FIG. 17B when the termination condition comprises expiration of acquisition process timer 84. The SI message acquisition process timer 84 is started at the beginning of the SI message acquisition process. The timer expiration value may be configured by the radio access node 22(17).

Thus, similar to the example embodiments and modes of FIG. 2 and FIG. 12, for acquisition of periodic broadcast-based SI message(s) as shown in FIG. 19 an extra mechanism to terminate the SI reception procedure may employed. In one configuration, the wireless terminal may use a counter, which is incremented at every SI window of a particular SI message (e.g. SI#k). In this configuration, the SI reception procedure triggered by acquiring may end when the requested SI message is successfully received, or when the counter reaches a maximum counter value. (It should be understood that this counter implementation is logically identical to an alternative implementation, wherein the counter is set with the maximum counter value at the beginning of the SI reception procedure and decremented upon the end of the SI window. In this implementation, the SI reception procedure may end when the counter becomes a pre-determined value, such as zero). In another configuration the wireless terminal starts a timer at the beginning of the SI reception procedure. In this configuration, the SI reception procedure may end when the requested SI message is successfully received, or when the timer expires. Similar to the embodiment of FIG. 12, and as understood by FIG. 18A and FIG. 18B, the maximum counter value, or the timer value, may be common for all SIB types, per-SIB type basis or per-SI message basis, may be pre-configured or configured by network via system information.

It should further be understood that a wireless terminal may be attempting to receive some second type SI by periodic broadcast, and one or more other second type SI by on-demand delivery. Hence, in a further example embodiment and mode the terminal processor 40 of a wireless terminal, such as wireless terminal 26(17), may be configured to both detect failure of a SI message acquisition process for broadcasted second type system information and detect failure of a SI message acquisition process for on-demand second type system information. For this reason the terminal processor 40 of wireless terminal 26(17) shows terminal processor 40 and SI processor 56 in particular as still comprising on-demand Other SI request generator 72. Thus it is possible in some modes for both the process of FIG. 14 and FIG. 19 to be executing essentially currently.

When a wireless terminal 26 is capable of both detecting failure of a SI message acquisition process for broadcasted second type system information and detecting failure of a SI message acquisition process for on-demand second type system information, the wireless terminal 26 may have separate termination conditions for each process. For that reason the wireless terminal 26 may comprise plural SI window counters 82 and/or plural SI message acquisition process timers 84. For example, the wireless terminal may have a first SI window counter 82(B) for a SI message acquisition process for broadcasted second type system information; and a second SI window counter 82(D) for a SI message acquisition process for on-demand second type system information. Or, for example, wireless terminal may have a first SI message acquisition process timer 84(B) for a SI message acquisition process for broadcasted second type system information; and a second SI message acquisition process timer 84(D) for a SI message acquisition process for on-demand second type system information.

Furthermore, the counter configuration or the timer configuration for acquisition of periodic broadcast-based SI message(s) may be configured via system information (e.g. SIB1) separately from the configuration for acquisition of on-demand based SI message(s). In this case, SIB1 shown in FIG. 13C with two separate counter configurations (si-MaxAcqAttemptsOnDemand and si-MaxAcqAttemptsPeriodic) or FIG. 13D with two separate timer configurations (T#x for on-demand and T#y for periodic broadcast) may be used. Alternatively, the counter/timer configuration common for on-demand and periodic broadcast-based SI message acquisition may be configured. In this case, SIB1 shown in FIG. 13A (common counter configuration) or FIG. 13B (common timer configuration) may be used.

The aforementioned more general 3GPP TS SI acquisition procedure for a UE to acquire the AS- and NAS information may be modified in part, e.g., for acquisition of an SI Message, for the example embodiment and mode of FIG. 19 as shown below. As indicated earlier, the counters (SI window counter 82(B) and SI window counter 82(D)) or the timers (SI message acquisition process timer 84(B) and SI message acquisition process timer 84(D)) may be identical, or alternatively separately configured.

When acquiring an SI message, the UE shall:

-   -   1> determine the start of the SI-window for the concerned SI         message as follows:     -   1> if SI message acquisition is not triggered due to UE request:         -   2> Set the counter SI window counter 82(B) to 0 (or Start             timer SI message acquisition process timer 84(B));         -   2> receive DL-SCH using the SI-RNTI from the start of the             SI-window and continue until the end of the SI-window whose             absolute length in time is given by si-WindowLength, or             until the SI message was received;         -   2> if the SI message was not received by the end of the             SI-window, increment the counter SI window counter 82(B),             repeat reception at the next SI-window occasion for the             concerned SI message;         -   2> if the counter SI window counter 82(B) is equal to             [configured maximum value] (or timer SI message acquisition             process timer 84(B) expires)             -   3> Initiate the SI acquisition procedure as defined in                 sub-clause 5.2.2.3.     -   1> else if SI message acquisition is triggered due to UE         request:         -   2> Set the counter SI window counter 82(D) to 0 (or Start             timer SI message acquisition process timer 84(D));         -   2>[receive DL-SCH using the SI-RNTI from the start of the             SI-window and continue until the end of the SI-window whose             absolute length in time is given by si-WindowLength, or             until the SI message was received];         -   2>[if the SI message was not received by the end of the             SI-window, increment the counter SI window counter 82(D),             repeat reception at the next SI-window occasion for the             concerned SI message];         -   2> if the counter SI window counter 82(D) is equal to             [configured maximum value] (or timer SI message acquisition             process timer 84(D) expires)             -   3> Initiate the SI acquisition procedure as defined in                 sub-clause 5.2.2.3.

Features from each of the example embodiments and modes described herein may be combined with one another. For example information elements described in conjunction with the example embodiment and mode of FIG. 2 may also be utilized with the other example embodiments and modes described herein, including but not limited to the example embodiment and mode of FIG. 14 and FIG. 19. Further, features of the “Example Embodiments” enumerated hereinafter may also be used in conjunction with one another.

Certain units and functionalities of node 22, node 22-12, node 22-17, wireless terminal 26, wireless terminal 26-14, and wireless terminal 26-17 are, in example embodiments, implemented by electronic machinery, computer, and/or circuitry. For example, the node processors 30 and terminal processors 40 of the example embodiments herein described and/or encompassed may be comprised by the computer circuitry of FIG. 23. FIG. 23 shows an example of such electronic machinery or circuitry, whether node or terminal, as comprising one or more processor(s) circuits 190, program instruction memory 192; other memory 194 (e.g., RAM, cache, etc.); input/output interfaces 196; peripheral interfaces 198; support circuits 199; and busses 200 for communication between the aforementioned units.

The program instruction memory 192 may comprise coded instructions which, when executed by the processor(s), perform acts including but not limited to those described herein. Thus is understood that each of node processor 30 and terminal processor 40, for example, comprise memory in which non-transient instructions are stored for execution.

The memory 194, or computer-readable medium, may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, flash memory or any other form of digital storage, local or remote, and is preferably of non-volatile nature. The support circuits 199 are coupled to the processors 190 for supporting the processor in a conventional manner. These circuits include cache, power supplies, clock circuits, input/output circuitry and subsystems, and the like.

Further, it should be understood that, when a processor or processor circuitry is mentioned in conjunction with any of the preceding example embodiments and modes, it should be understood that the device hosting the processor, whether wireless terminal or access node, may comprise at least one processor and at least one memory including computer program code, the memory and the computer program code being configured to, working with the at least one processor, to cause the host device to perform the functions afore-described.

Thus, the technology disclosed herein solves problems in the field of telecommunications, including problems in telecommunications nodes such wireless terminals and access nodes, as well as computers/processors and hardware comprising such nodes. System information is of utmost importance to the operation of telecommunication nodes, so that each node can obtain the necessary network information to coordinate and communicate with other nodes and to perform its desired functions. The system information is quite extensive and complex, and may be changeable/updateable due to network and operating conditions, for example. Efficiently obtaining and using the system information is challenging, particularly in view of numerous other telecommunications functions that may be simultaneously on-going based on the system information. The technology disclosed herein solves problem that may occur when SI messages are not timely received by, e.g., curtailing SI reception procedures and initiating remedial measures such as re-acquiring SIB1. The technology disclosed herein thus avoids waste of time and undue expenditure of processing resources.

The technology of this application thus encompasses but is not limited to the following example embodiments, example features, and example advantages, wherein the suffix “D” refers to an on-demand example embodiment and the suffix “B” refers to a periodic broadcast example embodiment:

Example Embodiment 1D

A user equipment that communicates over a radio interface with a base station apparatus of a radio access network (RAN), the user equipment comprising:

receiver circuitry configured to receive first type system information (SI) from the base station apparatus, the first type SI comprising:

-   -   availability of a second type SI message, the second type SI         message comprising at least one system information block (SIB);     -   scheduling information for the SI message;     -   an indication of a delivery mode for the second type SI message,         the delivery mode being either periodic broadcast or on-demand         basis; and     -   at least one termination condition for determination of a         failure of an SI message acquisition process;

transmitter circuitry configured to transmit an SI request message to request at least one second type SI message indicated as on-demand delivery;

processor circuitry configured:

-   -   to use the receiver circuitry to initiate the SI message         acquisition process;     -   to make a determination of a failure of the SI message         acquisition process based on the termination condition; and     -   upon a failure of the SI message acquisition process, to         initiate acquisition of the first type system information.

Example Embodiment 2D

The user equipment of Example Embodiment 1D, wherein the termination condition comprises a counter reaching a maximum value configured by the base station apparatus, the counter incremented in a case where the requested SI message was not received by the end of one reception opportunity.

Example Embodiment 3D

The user equipment of Example Embodiment 2D, wherein the reception opportunity is an SI window configured by the base station apparatus.

Example Embodiment 4D

The user equipment of Example Embodiment 1D, wherein the termination condition comprises a counter reaching zero from a preset value configured by the base station apparatus, the counter decremented in a case where the requested SI message was not received by the end of one reception opportunity.

Example Embodiment 5D

The user equipment of Example Embodiment 4D, wherein the reception opportunity is an SI window configured by the base station apparatus.

Example Embodiment 6D

The user equipment of Example Embodiment 1D, wherein the termination condition comprises an expiration of a timer configured by the base station apparatus, the timer starting upon start of the SI message acquisition process.

Example Embodiment 7D

A method for a user equipment that communicates over a radio interface with a base station apparatus of a radio access network (RAN), comprising:

receiving first type system information (SI) from the base station apparatus, the first type SI comprising:

-   -   availability of a second type SI message, the second type SI         message comprising at least one system information block (SIB);     -   scheduling information for the SI message;     -   an indication of a delivery mode for the second type SI message,         the delivery mode being either periodic broadcast or on-demand         basis;     -   at least one termination condition for determination of a         failure of an SI message acquisition process for the on-demand         based second type SI message;

transmitting an SI request message to request at least one second type SI message indicated as on-demand delivery;

initiating the SI message acquisition process;

determining a failure of the SI message acquisition process; and

upon a failure of the SI message acquisition process initiating acquisition of the first type system information.

Example Embodiment 8D

The method of Example Embodiment 7D, wherein the failure of the SI message acquisition process is determined by a counter reaching a maximum value configured by the base station apparatus, the counter incremented in a case where the requested SI message was not received by the end of one reception opportunity.

Example Embodiment 9D

The method of Example Embodiment 7D, wherein the reception opportunity is an SI window configured by the base station apparatus.

Example Embodiment 10D

The method of Example Embodiment 7D, wherein the failure of the acquisition process is determined by an expiration of a timer configured by the base station apparatus, the timer starting upon start of the SI message acquisition process.

Example Embodiment 11D

A base station apparatus of a radio access network (RAN) that communicates over a radio interface with a user equipment, the base station apparatus comprising:

transmitter circuitry configured to transmit first type system information (SI), the first type SI comprising:

-   -   availability of a second type SI message, the second type SI         message comprising at least one system information block (SIB);     -   scheduling information for the SI message;     -   an indication of a delivery mode for the second type SI message,         the delivery mode being either periodic broadcast or on-demand         basis;     -   a configuration parameter to configure at least one termination         condition for determination of a failure of an SI message         acquisition process for the on-demand second type SI message;

receiver circuitry configured to receive an SI request message to request at least one second type SI message;

processor circuitry configured to use the transmitter circuitry to deliver the requested SI message.

Example Embodiment 12D

The base station apparatus of Example Embodiment 11D, wherein the termination condition comprises a counter reaching a maximum value configured by the base station apparatus, the counter incremented in the case where the requested SI message was not received by the end of one reception opportunity.

Example Embodiment 13D

The base station apparatus of Example Embodiment 12D, wherein the reception opportunity is an SI window configured by the base station apparatus.

Example Embodiment 14D

The base station apparatus of Example Embodiment 11D, wherein the termination condition comprises an expiration of a timer configured by the base station apparatus, the timer starting upon start of the SI message acquisition process.

Example Embodiment 15D

A method for a base station apparatus of a radio access network (RAN) that communicates over a radio interface with a user equipment, comprising:

transmitting first type system information (SI), the first type SI comprising:

-   -   availability of a second type SI message, the second type SI         message comprising at least one system information block (SIB);     -   scheduling information for the SI message;     -   an indication of a delivery mode for the second type SI message,         the delivery mode being either periodic broadcast or on-demand         basis;     -   a configuration parameter to configure at least one termination         condition for determination of a failure of an SI message         acquisition process for the on-demand second type SI message;

receiving an SI request message to request at least one second type SI message;

delivering the requested SI message.

Example Embodiment 16D

The method of Example Embodiment 15D, wherein the termination condition comprises a counter reaching a maximum value configured by the base station apparatus, the counter incremented in the case where the requested SI message was not received by the end of one reception opportunity.

Example Embodiment 17D

The method of Example Embodiment 16D, wherein the reception opportunity is an SI window configured by the base station apparatus.

Example Embodiment 18D

The method of Example Embodiment 15D, wherein the termination condition comprises an expiration of a timer configured by the base station apparatus, the timer starting upon start of the SI message acquisition process.

Example Embodiment 19D

A user equipment that communicates over a radio interface with a base station apparatus of a radio access network (RAN), the user equipment comprising:

processor circuitry configured to initiate a first type system information block (SIB) acquisition process to receive a first type SIB, the first type SIB comprising:

-   -   scheduling information of a system information (SI) message, the         SI message comprising at least one second type SIB; and     -   an indication of broadcast status for the SI message, the         indication indicating on-demand delivery;

receiver circuitry configured to receive the first type SIB; and

transmitter circuitry configured to transmit an SI request message to request the SI message;

the processor circuitry further configured to initiate an SI message acquisition process to receive the SI message; wherein

in a case that a stored version of one of the at least one second type SIB is not valid, the first type SIB acquisition process is initiated upon a failure of the SI message acquisition process.

Example Embodiment 20D

The user equipment of Example Embodiment 19D, wherein the processor circuitry is further configured to re-initiate the SI message acquisition process based on the first type SIB acquisition process being initiated upon the failure of the SI message acquisition process.

Example Embodiment 21D

A method for a user equipment that communicates over a radio interface with a base station apparatus of a radio access network (RAN), the method comprising:

initiating a first type system information block (SIB) acquisition process to receive a first type SIB, the first type SIB comprising:

-   -   scheduling information of a system information (SI) message, the         SI message comprising at least one second type SIB; and     -   an indication of broadcast status for the SI message, the         indication indicating on-demand delivery;

receiving the first type SIB;

transmitting an SI request message to request the SI message; and

initiating an SI message acquisition process to receive the SI message; wherein

in a case that a stored version of one of the at least one second type SIB is not valid, the first type SIB acquisition process is initiated upon a failure of the SI message acquisition process.

Example Embodiment 22D

The method of Example Embodiment 21D, further comprising re-initiating the SI message acquisition process based on the first type SIB acquisition process being initiated upon the failure of the SI message acquisition process.

Example Embodiment 23D

A base station apparatus of a radio access network (RAN) that communicates over a radio interface with a user equipment, the base station apparatus comprising:

transmitter circuitry configured to transmit first type system information block (SIB), the first type SIB comprising:

-   -   scheduling information of a system information (SI) message, the         SI message comprising at least one second type SIB; and     -   an indication of broadcast status for the SI message, the         indication indicating on-demand delivery;

receiver circuitry configured to receive an SI request message to request the SI message;

processor circuitry configured to use the transmitter circuitry to deliver the SI message; wherein

the first type SIB is re-acquired by the user equipment upon the user equipment failing on an SI message acquisition process to receive the SI message, in a case that a version of one of the at least one second type SIB stored in the user equipment is not valid.

Example Embodiment 24D

The base station apparatus of Example Embodiment 23D, wherein the first type SIB re-acquired by the user equipment is used by the user equipment to re-initiate the SI message acquisition process.

Example Embodiment 25D

A method for a base station apparatus of a radio access network (RAN) that communicates over a radio interface with a user equipment, comprising:

transmitting first type system information block (SIB), the first type SIB comprising:

-   -   scheduling information of a system information (SI) message, the         SI message comprising at least one second type SIB; and     -   an indication of broadcast status for the second type SI         message, the indication indicating on-demand delivery;

receiving an SI request message to request the SI message;

delivering the SI message; wherein

the first type SIB is re-acquired by the user equipment upon the user equipment failing on an SI message acquisition process to receive the SI message, in a case that a version of one of the at least one second type SIB stored in the user equipment is not valid.

Example Embodiment 26D

The method Example Embodiment 25D, wherein the first type SIB re-acquired by the user equipment is used by the user equipment to re-initiate the SI message acquisition process.

Example Embodiment 1B

A user equipment that communicates over a radio interface with a base station apparatus of a radio access network (RAN), the user equipment comprising:

receiver circuitry configured to receive first type system information (SI) from the base station apparatus, the first type system information comprising:

-   -   availability of a second type SI message, the second type SI         message comprising at least one system information block (SIB);     -   scheduling information for the SI message;     -   an indication of a delivery mode for the second type SI message,         the delivery mode being either periodic broadcast or on-demand         basis; and     -   at least one termination condition for determination of a         failure of an SI message acquisition process;

processor circuitry configured:

-   -   to use the receiver circuitry to initiate the SI message         acquisition process for a periodically broadcasted second type         SI message;     -   to make a determination of a failure of the SI message         acquisition process based on the termination condition; and     -   upon a failure of the SI message acquisition process, to         initiate acquisition of the first type system information.

Example Embodiment 2B

The user equipment of Example Embodiment 1B, wherein the termination condition comprises a counter reaching a maximum value configured by the base station apparatus, the counter incremented in the case where the requested SI message was not received by the end of one reception opportunity.

Example Embodiment 3B

The user equipment of Example Embodiment 2B, wherein the reception opportunity is an SI window configured by the base station apparatus.

Example Embodiment 4B

The user equipment of Example Embodiment 1B, wherein the termination condition comprises an expiration of a timer configured by the base station apparatus, the timer starting upon start of the SI message acquisition process.

Example Embodiment 5B

The user equipment of Example Embodiment 1B, wherein the termination condition is also used for an SI message acquisition process of on-demand basis second type SI messages.

Example Embodiment 6B

The user equipment of Example Embodiment 1B, wherein the termination condition is dedicated for SI message acquisition process of periodically broadcasted basis second type SI messages.

Example Embodiment 7B

The user equipment of Example Embodiment 6B, wherein the first type SI further comprises at least one termination condition dedicated for the SI message acquisition process of on-demand basis second type SI messages.

Example Embodiment 8B

A method for a user equipment that communicates over a radio interface with a base station apparatus of a radio access network (RAN), comprising:

receiving first type system information (SI) from the base station apparatus, the first type system information comprising:

-   -   availability of a second type SI message, the second type SI         message comprising at least one system information block (SIB);     -   scheduling information for the SI message;     -   an indication of a delivery mode for the second type SI message,         the delivery mode being either periodic broadcast or on-demand         basis;     -   at least one termination condition for determination of a         failure of an SI message acquisition process;

initiating the SI message acquisition process for a periodically broadcasted second type SI message;

determining a failure of the SI message acquisition process; and

upon a failure of the SI message acquisition process, initiating acquisition of the first type system information.

Example Embodiment 9B

The method of Example Embodiment 8B, wherein the failure of the SI message acquisition process is determined by a counter reaching a maximum value configured by the base station apparatus, the counter incremented in the case where the requested SI message was not received by the end of one reception opportunity.

Example Embodiment 10B

The method of Example Embodiment 9B, wherein the reception opportunity is an SI window configured by the base station apparatus.

Example Embodiment 11B

The method of Example Embodiment 8B, wherein the failure of the acquisition process is determined by an expiration of a timer configured by the base station apparatus, the timer starting upon start of the SI message acquisition process.

Example Embodiment 12B

The method of Example Embodiment 8B, wherein the termination condition is dedicated for SI message acquisition process of periodically broadcasted basis second type SI messages.

Example Embodiment 13B

The method of Example Embodiment 12B, wherein the first type SI further comprises at least one termination condition dedicated for the SI message acquisition process of on-demand basis second type SI messages.

Example Embodiment 14B

A base station apparatus of a radio access network (RAN) that communicates over a radio interface with a user equipment, the base station apparatus comprising:

transmitter circuitry configured to transmit first type system information (SI), the first type SI comprising:

-   -   availability of a second type SI message, the second type SI         message comprising at least one system information block (SIB);     -   scheduling information for the SI message;     -   an indication of a delivery mode for the second type SI message,         the delivery mode being either periodic broadcast or on-demand         basis;     -   configuration parameters to configure for at least one         termination condition for determination of a failure of an SI         message acquisition process;

processor circuitry configured to use the transmitter circuitry to broadcast the periodic broadcast-based SI messages.

Example Embodiment 15B

The base station apparatus of Example Embodiment 14B, wherein the termination condition comprises a counter reaching a maximum value configured by the base station apparatus, the counter incremented in the case where the requested SI message was not received by the end of one reception opportunity.

Example Embodiment 16B

The base station apparatus of Example Embodiment 15B, wherein the reception opportunity is an SI window configured by the base station apparatus.

Example Embodiment 17B

The base station apparatus of Example Embodiment 14B, wherein the termination condition comprises an expiration of a timer configured by the base station apparatus, the timer starting upon start of the SI message acquisition process.

Example Embodiment 18B

The base station apparatus of Example Embodiment 14, wherein the termination condition is also used for an SI message acquisition process of on-demand basis second type SI messages.

Example Embodiment 19B

The base station apparatus of Example Embodiment 14B, wherein the termination condition is dedicated for SI message acquisition process of periodically broadcasted basis second type SI messages.

Example Embodiment 20B

The base station apparatus of Example Embodiment 19B, wherein the first type SI further comprises at least one termination condition dedicated for the SI message acquisition process of on-demand basis second type SI messages.

Example Embodiment 21B

A method for a base station apparatus of a radio access network (RAN) that communicates over a radio interface with a user equipment, comprising:

transmitting first type system information (SI) from the base station apparatus, the first type system information comprising:

-   -   availability of a second type SI message, the second type SI         message comprising at least one system information block (SIB);     -   scheduling information for the SI message;     -   an indication of a delivery mode for the second type SI message,         the delivery mode being either periodic broadcast or on-demand         basis;     -   configuration parameters to configure for at least one         termination condition for determination of a failure of an SI         message acquisition process;

broadcasting the periodic broadcast-based SI messages.

Example Embodiment 22B

The method of Example Embodiment 21B, wherein the termination condition comprises a counter reaching a maximum value configured by the base station apparatus, the counter incremented in the case where the requested SI message was not received by the end of one reception opportunity.

Example Embodiment 23B

The method of Example Embodiment 22B, wherein the reception opportunity is an SI window configured by the base station apparatus.

Example Embodiment 24B

The method of Example Embodiment 21B, wherein the termination condition comprises an expiration of a timer configured by the base station apparatus, the timer starting upon start of the SI message acquisition process.

Example Embodiment 25B

The method of Example Embodiment 21B, wherein the termination condition comprises an expiration of a timer configured by the base station apparatus, the timer starting upon start of the SI message acquisition process.

Example Embodiment 26B

The method of Example Embodiment 21B, wherein the termination condition is also used for an SI message acquisition process of on-demand basis second type SI messages.

Example Embodiment 27B

The method of Example Embodiment 25B, wherein the termination condition is dedicated for SI message acquisition process of periodically broadcasted basis second type SI messages.

Although the processes and methods of the disclosed embodiments may be discussed as being implemented as a software routine, some of the method steps that are disclosed therein may be performed in hardware as well as by a processor running software. As such, the embodiments may be implemented in software as executed upon a computer system, in hardware as an application specific integrated circuit or other type of hardware implementation, or a combination of software and hardware. The software routines of the disclosed embodiments are capable of being executed on any computer operating system, and is capable of being performed using any CPU architecture. The instructions of such software are stored on non-transient computer readable media.

The functions of the various elements including functional blocks, including but not limited to those labeled or described as “computer”, “processor” or “controller”, may be provided through the use of hardware such as circuit hardware and/or hardware capable of executing software in the form of coded instructions stored on computer readable medium. Thus, such functions and illustrated functional blocks are to be understood as being either hardware-implemented and/or computer-implemented, and thus machine-implemented.

In terms of hardware implementation, the functional blocks may include or encompass, without limitation, digital signal processor (DSP) hardware, reduced instruction set processor, hardware (e.g., digital or analog) circuitry including but not limited to application specific integrated circuit(s) [ASIC], and/or field programmable gate array(s) (FPGA(s)), and (where appropriate) state machines capable of performing such functions.

In terms of computer implementation, a computer is generally understood to comprise one or more processors or one or more controllers, and the terms computer and processor and controller may be employed interchangeably herein. When provided by a computer or processor or controller, the functions may be provided by a single dedicated computer or processor or controller, by a single shared computer or processor or controller, or by a plurality of individual computers or processors or controllers, some of which may be shared or distributed. Moreover, use of the term “processor” or “controller” shall also be construed to refer to other hardware capable of performing such functions and/or executing software, such as the example hardware recited above.

The functions of the various elements including functional blocks, including but not limited to those labeled or described as “computer”, “processor” or “controller”, may be provided through the use of hardware such as circuit hardware and/or hardware capable of executing software in the form of coded instructions stored on computer readable medium. Thus, such functions and illustrated functional blocks are to be understood as being either hardware-implemented and/or computer-implemented, and thus machine-implemented.

Nodes that communicate using the air interface also have suitable radio communications circuitry. Moreover, the technology can additionally be considered to be embodied entirely within any form of computer-readable memory, such as solid-state memory, magnetic disk, or optical disk containing an appropriate set of computer instructions that would cause a processor to carry out the techniques described herein.

It will be appreciated that the technology disclosed herein is directed to solving radio communications-centric issues and is necessarily rooted in computer technology and overcomes problems specifically arising in radio communications. Moreover, in at least one of its aspects the technology disclosed herein improves the functioning of the basic function of a wireless terminal and/or node itself so that, for example, the wireless terminal and/or node can operate more effectively by prudent use of radio resources.

Although the description above contains many specificities, these should not be construed as limiting the scope of the technology disclosed herein but as merely providing illustrations of some of the presently preferred embodiments of the technology disclosed herein. Thus the scope of the technology disclosed herein should be determined by the appended claims and their legal equivalents. Therefore, it will be appreciated that the scope of the technology disclosed herein fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the technology disclosed herein is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the technology disclosed herein, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.” 

What is claimed is:
 1. A user equipment that communicates over a radio interface with a base station apparatus of a radio access network (RAN), the user equipment comprising: processor circuitry configured to initiate a first type system information block (SIB) acquisition process to receive a first type SIB, the first type SIB comprising: scheduling information of a system information (SI) message, the SI message comprising at least one second type SIB; and an indication of broadcast status for the SI message, the indication indicating on-demand delivery; receiver circuitry configured to receive the first type SIB; and transmitter circuitry configured to transmit an SI request message to request the SI message; the processor circuitry further configured to initiate an SI message acquisition process to receive the SI message; wherein in a case that a stored version of one of the at least one second type SIB is not valid, the first type SIB acquisition process is initiated upon a failure of the SI message acquisition process.
 2. The user equipment of claim 1, wherein the processor circuitry is further configured to re-initiate the SI message acquisition process based on the first type SIB acquisition process being initiated upon the failure of the SI message acquisition process.
 3. A method for a user equipment that communicates over a radio interface with a base station apparatus of a radio access network (RAN), the method comprising: initiating a first type system information block (SIB) acquisition process to receive a first type SIB, the first type SIB comprising: scheduling information of a system information (SI) message, the SI message comprising at least one second type SIB; and an indication of broadcast status for the SI message, the indication indicating on-demand delivery; receiving the first type SIB; transmitting an SI request message to request the SI message; and initiating an SI message acquisition process to receive the SI message; wherein in a case that a stored version of one of the at least one second type SIB is not valid, the first type SIB acquisition process is initiated upon a failure of the SI message acquisition process.
 4. The method of claim 3, further comprising re-initiating the SI message acquisition process based on the first type SIB acquisition process being initiated upon the failure of the SI message acquisition process.
 5. A base station apparatus of a radio access network (RAN) that communicates over a radio interface with a user equipment, the base station apparatus comprising: transmitter circuitry configured to transmit first type system information block (SIB), the first type SIB comprising: scheduling information of a system information (SI) message, the SI message comprising at least one second type SIB; and an indication of broadcast status for the SI message, the indication indicating on-demand delivery; receiver circuitry configured to receive an SI request message to request the SI message; processor circuitry configured to use the transmitter circuitry to deliver the SI message; wherein the first type SIB is re-acquired by the user equipment upon the user equipment failing on an SI message acquisition process to receive the SI message, in a case that a version of one of the at least one second type SIB stored in the user equipment is not valid.
 6. The base station apparatus of claim 5, wherein the first type SIB re-acquired by the user equipment is used by the user equipment to re-initiate the SI message acquisition process.
 7. A method for a base station apparatus of a radio access network (RAN) that communicates over a radio interface with a user equipment, comprising: transmitting first type system information block (SIB), the first type SIB comprising: scheduling information of a system information (SI) message, the SI message comprising at least one second type SIB; and an indication of broadcast status for the second type SI message, the indication indicating on-demand delivery; receiving an SI request message to request the SI message; delivering the SI message; wherein the first type SIB is re-acquired by the user equipment upon the user equipment failing on an SI message acquisition process to receive the SI message, in a case that a version of one of the at least one second type SIB stored in the user equipment is not valid.
 8. The method of claim 7, wherein the first type SIB re-acquired by the user equipment is used by the user equipment to re-initiate the SI message acquisition process. 